不同草地建植模式对荒坡地土壤风蚀及理化性质的影响

Effects of Different Eco-grassland Models on Soil Wind Erosion and Physical and Chemical Properties on the Barren Slope

荒坡地土壤贫瘠、植被稀疏,冬春季风蚀沙化严重,试验在密云水库库区荒坡地构建不同生态草地建植模式,研究草地建植对土壤理化性质改善作用和土壤风蚀防治效果,结果表明,生态草地建植当年地上生物量达2 246.9kg/hm2以上,越年后明显增加,可达5 941.6kg/hm2;生态草地建植可使荒坡地地表粗糙度增加1.7～14.5倍,土壤风蚀减少44.9%～75.1%,其中,草地雀麦+扁穗冰草建植模式地表粗糙度增加效果最佳,且不同建植模式土壤风蚀防治效果顺序为草地雀麦+扁穗冰草建植模式>草地雀麦+老芒麦建植模式>披碱草建植模式>草地雀麦+草木樨草建植模式>草地雀麦建植模式;同时,荒坡地生态草地建植可以降低土壤容重,增加总孔隙度,改善土壤物理性质,其中,草地雀麦+老芒麦草地建植1a,可使土壤容重降低8.7%,总孔隙度增加16.1%,荒坡地草地建植还可增加土壤有机质,降低土壤pH值,提高速效氮含量,草地雀麦+老芒麦建植模式与草地雀麦建植模式构建1a,土壤速效氮增加75.4%～79.1%。

There was less vegetation on the barren slope due to less nutrition in the soil so that wind erosion and desertification occurred more badly.The experimentation was carried into execution to design different eco-grassland models to prevent wind erosion and improve soil physical and chemical properties in the barren slope in the Miyun reservoir watershed.The results showed that there was more 2 246.9 kg/hm2 of overground biomass in the year when eco-grasslands were planted.And it added to 5 941.6 kg/hm2 greatly next year.Roughness length on the barren slope increased by 1.7~14.5 times after eco-grassland was planted,and soil wind erosion decreased by 44.9%~75.1%.Especially the roughness length of eco-grassland model of Bromus riparius＋Agropyron cristatum increased the most than the others.And the effects of eco-grassland models on preventing wind erosion were Bromus riparius＋Agropyron cristatumBromus riparius＋Elymus sibiricusElymus dahuricusBromus riparius＋Melilotus suaveolensBromus riparius.On the other hand,soil bulk density reduced,and soil porosity increased after eco-grasslands were planted.Furthermore,soil organic matter and available nitrogen increased,and pH decreased significantly.So soil physical and chemical properties changed batter.Especially,the soil bulk density of eco-grassland of Bromus riparius＋Elymus sibiricus reduced by 8.7%,and the soil porosity increased 16.1% in a year.And available nitrogen of Bromus riparius＋Elymus sibiricus eco-grassland and simple Bromus riparius eco-grassland increased by 75.4%~79.1%.